Method and apparatus for manipulating metal workpieces

ABSTRACT

A method of forming a duct section from a web of material includes the steps of forming a series of perforations in a web of material, the series of perforations defining an outline of one of a hole or notch in a finished duct section, forming a male lock bend and a female lock seam in first opposed edges of the web of material, forming flanges in second opposed edges of the web of material, removing the portion of material interior to the series of perforations to form the hole or notch, and bending the web of material to form the finished duct section.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/817,428, filed Nov. 20, 2017, which claims the benefit ofU.S. Provisional Application Ser. No. 62/425,297, filed on Nov. 22,2016, both of which are hereby incorporated by reference their entirety.

FIELD OF THE INVENTION

The present invention relates generally to manipulating metal workpiecesand, more particularly, to a method and apparatus for forming featuresin a sheet of material for subsequent bending into an HVAC duct section.

BACKGROUND OF THE INVENTION

A plasma cutter is a cutting tool used in manufacturing industries forcutting electrically conductive materials such as steel, aluminum, brassand copper. Plasma cutters work by creating an electrical channel ofsuperheated, electrically ionized gas (“plasma”) from the plasma cutter,through the material to be cut, thus forming a completed circuit back tothe plasma cutter via a grounding clamp. This is accomplished by forcinga compressed gas (e.g., oxygen, nitrogen, argon shop air, etc.) througha focused nozzle at high speed toward the workpiece/material to be cut.An electrical arc is then formed within the gas, between an electrodenear or integrated into the gas nozzle and the work piece itself. Theelectrical arc ionizes some of the gas, thereby creating an electricallyconductive channel of plasma. As electricity from the torch travels downthis plasma, it delivers sufficient heat to melt through the workpiece.At the same time, much of the high velocity plasma and compressed gasblow the hot molten metal away, thereby separating i.e. cutting throughthe work piece. In recent years, plasma cutters have been integratedwith computer numeric control systems, providing greater flexibility forthe plasma cutter to cut diverse shapes in workpiece, based on theinstructions programmed into the machine's numerical control.

In HVAC industry, box-shaped ducts are extensively used in heating andventilating systems to distribute heated or cooled air throughout astructure. The ducts are commonly formed in sections of predeterminedlength, which are then connected end-to-end to form a continuous airdistribution duct. The material from which the duct sections are formedis typically sheet of material of a desired gauge fed from a roll orcoil of material. Recently, plasma cutters have been employed in theduct fabrication process, such as to cut the sheet material into shapesand configurations necessary for forming the duct sections, and to formnotches, taps, access doors and the like in such duct sections.Typically, these cuts are made in the sheet material prior to bendinginto a completed duct section. As will be readily appreciated, formingstructures such as notches, taps, and access doors in the sheet materialrequires flexible moving of the plasma cutter over the sheet material.

While the use of plasma cutters has proven advantageous to the ductfabrication process, certain drawbacks do exist. For example, removingquantities of material from the sheet material to form notches, taps,access doors and like features prior to bending into a completed ductsection can greatly reduce the integrity of the sheet material,rendering it less structurally sound and making the subsequent rollingand bending processes much more difficult.

In view of the above, there is a need for an improved method andapparatus for fabricating HVAC duct sections using a plasma cutter

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method andapparatus for manipulating a metal workpiece.

It is an object of the present invention to provide a method andapparatus for fabricating HVAC duct sections.

It is an object of the present invention to provide a method andapparatus for forming notches, taps, access doors and related featuresin HVAC duct sections.

It is an object of the present invention to provide a method andapparatus for forming notches, taps, access doors and related featuresin HVAC duct sections, which does not compromise the integrity of thesheet material prior to bending.

It is an object of the present invention to provide a method andapparatus for fabricating HVAC duct sections more quickly andefficiently, and at a lower cost, as compared to existing methods anddevices.

These and other objects are achieved by the present invention.

According to an embodiment of the present invention, a method ofmanipulating a sheet of material includes loading cutting parameter datainto a controller, the cutting parameter data defining an architectureof at least one feature to be formed in a sheet of material, and forminga series of perforations in the sheet of material in accordance with thecutting parameter data, the series of perforations forming an outline ofthe at least one feature.

According to another embodiment of the preset invention an apparatus formanipulating a sheet of material includes a cutting table for supportinga sheet of material, a cutting device positioned adjacent to the cuttingtable, and a controller operatively connected to the cutting device andconfigured to control a position of the cutting device with respect tothe cutting table. The controller is further configured to control thecutting device to form a series of perforations in the sheet ofmaterial, wherein the series of perforations define an architecture ofat least one feature to be formed in the sheet of material.

According to yet another embodiment of the present invention, a methodof forming a duct section from a web of material includes the steps offorming a series of perforations in a web of material, the series ofperforations defining an outline of one of a hole or notch in a finishedduct section, forming a male lock bend and a female lock seam in firstopposed edges of the web of material, forming flanges in second opposededges of the web of material, removing the portion of material interiorto the series of perforations to form the hole or notch, and bending theweb of material to form the finished duct section.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 is a top plan view of a sheet of material having featuresproduced using a plasma cutter of the prior art.

FIG. 2 is a schematic plan view of a production line on which aworkpiece is manipulated and formed into ventilation duct.

FIG. 3 is a simplified schematic illustration of a plasma cuttingstation of the production line of FIG. 2.

FIG. 4 is a top plan view of a sheet of material having featuresproduced using the method and apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a sheet of material processed by a plasma cutter ofthe prior art. The sheet of material 10 may take the form of any type ofelectrically conductive material known in the HVAC industry formanufacturing a ventilation duct such as, for example, steel, aluminum,brass, copper, etc. As is known in the art, when a plasma cutter (notshown) is applied to the sheet of material 10, an electrical channel ofsuperheated, electrically ionized gas is continuously blown through afocused nozzle at high speed toward the surface of the sheet of material10, melting through the sheet of material 10 by delivering sufficientheat toward its surface, while the head of the plasma cutter moves abovethe sheet of material. A plasma cutter can therefore be used to createvarious features in a sheet of material such as sheet metal. Asillustrated in FIG. 1, for example, a continuous hole seam 12 can becreated by the plasma cutter to form a hole 11 in the material, and/or acontinuous notch seam 14 can be cut on the corner of the sheet ofmaterial 10 by the plasma cutter to create a notch 13. Therefore, bycontrolling the moving pathway of the plasma cutter, various types ofstructures and features can be created on the sheet of material 10including, but not limited to, holes, notches, taps, access doors, etc.With existing methods and apparatuses, however, all the cutting seamscreated by the plasma cutter are continuous, and hence the cut offportion of the sheet of material 10, such as the portion of materialwithin the hole 11 or notch 13, are removed completely upon conclusionof the plasma cutting process.

Turning now to FIG. 2, a system 100, in the form of a production linefor forming metal HVAC ducts from a thin sheet of material according toan embodiment of the present invention is illustrated. As shown therein,the system 100 includes at least, a start end 110, a first station 120,a second station 140, a third station 160, and a finish end 180. At thestart end 110, a sheet of material, preferably sheet metal, of a desiredgauge and width is supplied in large rolls or coils. As is well known tothose skilled in the art, the sheet of material from one of the coils isfed by a feeder (not shown) into the first station 120.

In an embodiment, the first station 120 may include a coil straightener,a plasma cutting table, a shearing section, and a plasma cutter, whicheach may take one of various forms known in the art. The coilstraightener contains a plurality of rolls that will remove the set inthe material caused by it being wound on a coil. The coil straightenerthus straightens the sheet of material and feeds the sheet of materialto the plasma cutting table where the sheet is cut to size and variousfeatures are cut in the material, as discussed below.

As best shown in FIG. 3, the plasma cutting section of the first station120 includes a plasma cutting table 210 supporting a sheet of material212 after it has been unwound from the rolls and straightened with thecoil straightener. The plasma cutting section also includes a plasmacutter 214 suspended above, and spaced from, the plasma cutting table210. As shown therein, the plasma cutter 214 is preferably mounted on atrack for movement along a pair of axes 216, 218 such that plasma cutter214 is capable of being positioned over any point above the table 210and sheet of material 212. The plasma cutter may generally take the formof any plasma cutting device known in the art, and is electricallyconnected to a power source (not shown) and a controller 220 (orotherwise in communication with the controller 220). As discussed indetail hereinafter, the controller 220 is configured to control themovement of the plasma cutter 220 along the axes 216, 218. In addition,in certain embodiments, the controller 220 may also be configured tocontrol the height of the plasma cutter 214 with respect to the sheet ofmaterial 212. Importantly, the controller 220 is configured to controloperation of the plasma cutter 214, and the position thereof withrespect to the sheet of material 212, according to a schematic diagramand/or cutting diagram for the sheet of material 212 stored in memory,as discussed hereinafter.

In the preferred embodiment, the controller 220 and/or plasma cutter 214is capable of downloading a blueprint or other technical drawings,diagrams or cutting positional data (also referred to as cuttingparameter data that defines an architecture of features to be formed ina finished duct section) for cutting the sheet of material from most CADMEP/Revit software packages. In an embodiment, the controller 220 hasinput/output capabilities so that user can also design and input theblueprints or technical drawings for plasma cutting into the controller220, allowing for custom cutting of features and other structures on thesheet of material 212. The blueprints/cutting data can be eitherpre-entered from the controller prior to the plasma cutting process, orentered simultaneously while the plasma cutting is conducted on thesheet of material. The moving pathway of the plasma cutter during theplasma cutting process is determined by the cutting data it receivesfrom the controller 220.

In an embodiment, during the plasma cutting process, the plasma cutter214 selectively moves, under control of the controller 220, in at leasttwo directions. In particular, the plasma cutter 214 is capable ofmoving along one X axis (e.g., axis 216) and one Y axis (e.g., axis218). In an embodiment, The X axis neither overlaps nor is parallel tothe Y axis. In an embodiment, the X axis is orthogonal to the Y axis. Inanother embodiment, the angle formed by the X axis and Y axis can be anydegree between zero to one hundred and eighty degrees. Being capable ofmoving along unparalleled X axis and Y axis, the moving range of theplasma cutter 214 covers the entire area of the plasma cutting table210. Therefore, the plasma cutter can be positioned automatically toreach to any single point on the sheet of material 212 for cutting anydesired structures, without manually adjusting the position of the sheetof material 212.

The controller 220 is operable to control the plasma cutter 214 to makecontinuous cuts in the sheet of material 212, so as to completely removea portion of material from the sheet to form hole 21 and notch 23, asshown in FIG. 1, as well as other shapes and structures. Importantly,however, the controller 220 and plasma cutter 220 are also operable tocreate perforated cuts (more generally, perforations) in the sheet ofmaterial 212. In this respect, the plasma cutter 214 is operable in botha continuous cutting mode or a perforated cutting mode.

For example, as shown in FIG. 4, during operation, plasma created by theplasma cutter 214 is directed toward the surface of a sheet of material(e.g., sheet of material 20) and melts through the sheet of material 20to create a cutting seam 22. However, in the perforated cutting mode,instead of a continuous seam such as those formed by known systems anddevices, such as continuous hole seam 12 and continuous notch seam 14,the cutting seam 22 created by the plasma cutter of the presentinvention may be intermittent or perforated. In particular, theperforated seam 22 includes a series of perforations 25, cut by theplasma cutter 214, and small webs 26 of material which are not removedfrom the sheet 20 (but which remain intact after the plasma cuttingprocess). Hence, the outline of a hole 21 is formed by the perforatedseam 22. The web of material 28 (also referred to as a blank orknock-out) interior to the perforated seam 22 remains partially attachedto the metal sheet 20 due to the small webs 26 of material connected theblank 28 to the larger sheet of material. A perforated outline for anotch 23 can also be created by the plasma cutter in the same manner, byforming a series of perforations and interposed webs in the shape of thenotch 23. Like the hole 21, importantly, the web of material formingundetached notch 23 remains attached to the sheet of material 20 afterthe plasma cutting process is complete.

Perforated cutting may be carried out by selectively activating anddeactivating the plasma cutter 214 as it moves along the pre-programmedpathway. In an embodiment, deactivating the plasma cutter may include,for example, interrupting the supply of power to the plasma cutter orinterrupting the supply of gas to the plasma cutter. In otherembodiments, perforated cuts may be made by increasing the spacingdistance of the plasma cutter 214 from the sheet of material so that theplasma cutter does not cut through the sheet.

Importantly, by preserving the partial attachment between the web ofmaterial defining the undetached holes 21 or undetached notch 23 and themetal sheet 20, the structural integrity of the metal sheet 20 ismaintained, which has heretofore not been possible with prior artsystems and methods. In particular, existing methods of cutting variousfeatures such as holes, doors, notches and the like in the sheet ofmaterial (where the material is completely removed during the cuttingprocess) can compromise the structural integrity of the sheet, making itdifficult to perform downstream manipulations of the sheet. Bymaintaining the structural integrity of the sheet after the formation ofholes, doors, notches and the like, by creating a perforated outline ofsuch features, however, subsequent processing of the material such as byrolling and bending into completed duct sections, can be more easilyeffected.

Referring once again to FIG. 2, after the plasma cutting of the featuresin accordance with the stored cutting data is completed, the sheet ofmaterial 212 then moves forward, from bottom to top in FIG. 2, into theshearing section of the first station 120. The processed portion of thesheet of material 212 is sheared off from the coil by the plasma cutter214 (e.g., by making a continuous cut across the sheet). It should alsobe noted that, in the present invention, cutting of all types ofstructures and features, including shearing, can be accomplished by oneplasma cutter on the plasma cutting table in the first station, therebysaving time and reduce the number of the plasma cutter needed.

After the processed portion of the sheet of material is sheared off atthe shearing section of the first station 120, the sheet of materialmoves forward along an axis of travel and enters into the second station140. The second station 140 is positioned in line orthogonal to thefirst axis of travel of the sheet of material. At the second station140, the pathway traveled by the sheet of material defines a second axisof travel that is orthogonal to the first axis of travel of the sheet ofmaterial. The second station 140 includes a male lock seam rollingformer and a female lock seam roll former. A pair of male and femalelock seams formed by the rolling formers in a manner known in the art.The roll former may generally take the form of any roll former commonlyknown in the art that is utilized to form various style lock seams. Inparticular, the roll former may be configured to form any style oflockseam, such as a Pittsburgh seam or Snaplock seam. The male andfemale lock seam are formed on opposite sides of the sheet of materialby the rolling former. In one embodiment, the male and female lock seamsare formed on the upper and bottom edges of the sheet of material. Inanother embodiment, the male and female lock seams are formed on theright and left side of the sheet of material.

After formation of the male and female lock seams, the sheet of materialforward to the third station 160. As illustrated in FIG. 2, the thirdstation 160 is arranged substantially parallel to the first station 120and is orthogonal to the second station 140. Within the third station160, the sheet of material moves along a third axis that is orthogonalto the second axis of travel of sheet of material, and is parallel butin an opposite direction as to the first axis of travel of the sheet ofmaterial. At the third station 160, duplex flanges are formed by flangeroll formers on a pair of opposite sides of the sheet of material. Theflange roll formers may take any form known in the art for forming anytype of transverse flange known in the art. It should be noted that theduplex flanges are formed on the sides opposite from the male and femalelock seams are

In an embodiment, additional plasma cutting can be accomplished in thethird station 160, utilizing either the same plasma cutter 214 used atthe first station 120, or a separate, additional plasma cutter. Where asingle plasma cutter is utilized, the tracks 216, 218 are of a lengthsufficient to allow movement of the plasma cutter 214 between the firststation 120 and the third station 160. In an embodiment, the plasmacutter 214 may be mounted for movement to any position above thesystem/production line 100, to carry out a variety of cuttingoperations. For example, at the third station 160, additional featuressuch as notches, holes, taps, access doors and etc. can be cut into thesheet of material, as desired.

After the flanges are completed in the third station 160, the processedsheet of material moves forward and enters into the finished end 180. Inthe finished end 180, the blanks/knock-outs formed by the perforatedcuts, such like the hole portion 21 and notch portion 23 in FIG. 4,which have remained attached to the sheet of material during the rollingforming operations, are removed, either manually or automatically. Theprocessed sheet of material is then transferred to a bending brake (notshown) where three 90 degree bends are made, and the male and femalelock seams are assembled to form the box-shaped duct section.

In an embodiment, the apparatus 100 may include a computer orprogrammable logic controller (not shown) and a plurality of switches,sensors and timers that operate in conjunction with one another andaccording to a set of instructions stored in memory. The computer orprogrammable logic controller can be the same controller for controllingthe plasma cutter, or can be a separate computer. In particular, all ofthe operational sequences for forming a completed duct section may becarried out automatically under the control of the computer orprogrammable logic controller in concert with the switches, sensors andtimers.

As discussed above, the method and apparatus of the present inventiontherefore provide a means to create various holes, notches, accessdoors, windows, slits and other features in a sheet of material withoutcompromising the structural integrity and rigidity of the material whichis necessary to carry out downstream roll forming and bending operationson the sheet. In particular, by creating perforated cuts that definesuch holes, notches, access doors, windows, slits and other features inthe sheet of material while the sheet is flat, large voids in the sheetare not present during subsequent roll forming and bending operations.Indeed, the material interior to the perforated cuts can easily beremoved using manual or automatic punching means after such roll formingand/or bending operations. As such, the structural integrity of thesheet of material is maintained until very near the end of the ductfabrication process, providing for a level of precision and ease ofassembly heretofore not seen in the prior art.

While the embodiments described above utilize a plasma cutter to makeperforated cuts in the sheet of material, it is contemplated that othermeans may also be employed to make such perforated cuts such as, forexample, mechanical cutting, punching or machining devices or lasers(e.g., a fiber laser).

Although this invention has been shown and described with respect to thedetailed embodiments thereof, it will be understood by those of skill inthe art that various changes may be made and equivalents may besubstituted for elements thereof without departing from the scope of theinvention. In addition, modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodimentsdisclosed in the above detailed description, but that the invention willinclude all embodiments falling within the scope of this disclosure.

What is claimed is:
 1. An apparatus for manipulating a sheet of materialto form a duct body, said apparatus comprising: a platen for supportingsaid sheet of material; a plasma cutting apparatus positioned adjacentsaid platen and arranged for movement with respect to said platen; acontrol system in communication with said plasma cutting apparatus, saidcontrol system selectively communicating cutting parameter data definingan architecture of a feature to be formed in said sheet of material, tosaid plasma cutting apparatus; and wherein said plasma cutting apparatusis selectively moved by said control system in accordance with saidcutting parameter data, said plasma cutting apparatus selectivelyadjusting a distance between said platen and said plasma cuttingapparats during an active cutting operation of said plasma cuttingapparatus.
 2. The apparatus for manipulating a sheet of material to forma duct body according to claim 1, wherein: said control systemselectively controls said plasma cutting apparatus to issue anon-continuous plasma beam from said plasma cutting apparatus so as toform discrete perforations defining said architecture.
 3. The apparatusfor manipulating a sheet of material to form a duct body according toclaim 1, wherein: said control system selectively controls said plasmacutting apparatus to issue a continuous plasma beam from said plasmacutting apparatus when forming said architecture.
 4. An apparatus formanipulating a metal workpiece to form a duct body, said apparatuscomprising: a surface for supporting said metal workpiece; a plasmatorch positioned adjacent said surface and arranged for movement withrespect to said metal workpiece; a control system in communication withsaid plasma torch, said control system selectively communicating cuttingparameter data defining an architecture of a feature to be formed insaid sheet of material, to said plasma cutting apparatus; and whereinsaid plasma cutting apparatus is selectively moved by said controlsystem in accordance with said cutting parameter data to ablate awaymaterial of said metal workpiece along a path defined by saidarchitecture.
 5. The apparatus for manipulating a sheet of material toform a duct body according to claim 4, wherein: said control systemcycles said plasma torch on and off during said ablation of saidmaterial along a path defined by said architecture, thereby forming aseries of perforations in said metal workpiece.
 6. The apparatus formanipulating a sheet of material to form a duct body according to claim4, wherein: said control system adjusts the distance between the metalworkpiece and said plasma torch during said ablation of said materialalong a path defined by said architecture.
 7. The apparatus formanipulating a sheet of material to form a duct body according to claim4, wherein: said control system adjusts an intensity of said plasmatorch during said ablation of said material along a path defined by saidarchitecture.